Method of and means for dehydrating fruits and vegetables



c. c. MaCPHERRAN Filed July 24, 1922 Oct. 12 ,1926.

METHOD 0F AND MEANS FOR DVEHYDRATI'NG FRUITS AND VEGETABLES PatentedOct. 12, 1926.

UNITED STATESV PATENT. oFjE1'cE.,lj-

(IHARLES C. MAOPHERRAN, 0F SEATTLE, WASHINGTONr f METHOD or AND MEANSron nEHYDnATmG FRUITS Ann .vnnrannns- Application llled July 24, 1922..Serial No. '577,148. 4: n A

This invention relates to a method of and means for dehydrating fruitsand vegetables, and has for its principal object to provide adehydrating apparatus wherem 5 the material may be started in anatmosthere is employed a plurality of horizontally moving belts,alternately operating in opposite directions and so arranged as todeliver material from one to the other until it has been advancedthrough the machine from normal temperature and high humidity through aconstantly increasing temperature and lowered relative humidity to thefinished stage.

Other objects reside in the details of construction of the apparatuswhich provides for automatic operation from start to completion andwhereby handling by human hands is eliminated.

In accomplishing these and other objects of the invention, I haveprovided the improved details of construction, the preferred forms ofwhich are illustrated in the accompanying drawings, wherein- Figure 1 isa perspective view showing in longitudinal, vertical section, adehydrating machine embodied by the present invention. Figure 2 is adetailed perspective view showing the belt driving means and a crosssectional view of the oven.

4Referring more in detail to the drawings:

LdeSignates, as a whole, the dehydrating oven, which preferably would beof metal construction, rectangular in form and of any desired orsuitable dimensions which would provide space for the required number ofconveying belts and which would permit the belts to be of considerablelength.

Mounted on the top wall 2 of the oven, and near one end thereof, is ahopper 3 into which the fruit, or vegetables, to be dehydrated areplaced and froinwhichthey are fed automatically, through an opening 4,into the oven and onto one :end of a continuous conveyor belt. 5. Thisvbelt o is mounted to operatepabout'v rollers 6 andi( supported at theirends from the. opposite side walls of the oven and in the samehorizontal plane at opposite ends of the oven, and is driven, aspresently will be described, so that the upper part thereof' travelsbeneath the hopper opening and toward the opposite end of the oven.`Cleats "8 are fixed transversely on the belt at regularly spacedintervals, which automatically feed the ma` terial from the hopper intothe machine and deliver it from the opposite end of the belt onto theupper portion of an oppositely moving belt 9 located at a spaced inter`val beneath the belt 5 and operating, at its ends, about rollers 11 and12. A wall 2 is placed in the oven parallel with the to wall and spacedlslightly therefrom, whic serves as a means of supporting the lowersection of belt 5, and also provides an upper warming oven 10separatefrom the'dehydrating oven proper.

The cleats 8 while serving as means for feeding the material into theoven are pri-- marily for the purpose of preventing the escape of airfrom the oven through the feeding opening. These cleats preferablyvwould be of a flexible character so thatthey will not cause mashing ofthe product. An-

other purpose of the cleats 8 is to provide means whereby the product tobe dehydrated, after entering the machine, is isolated in practicallyair tight compartments between the cleats and may be heated as it ispassed through the warming oven.10 to a properI temperature fordehydration before it enters the dehydrating atmosphere. The characterof the cleats used and their position is immaterial so long as thisresult 1s accomplished, and the result may 'be arrived at by othermeans. y

Sup orted successively, one below the other, 1n parallel relation as'are the belts 5 and 9, and at spaced apart intervals, are belts 13,14.-, 15, 16 and 17 which, in the order named, operate at their oppositeends about rollers 19 and 20, 21 and 22, 23 and 24, 25 and 26, and 27and 28, which are f each will receive thereon the material deliveredfrom the end of the next higher belt and the belts are so operated thatthey will advance this material to their opposite ends and there deliverit onto the next lower belt. In this way the materialis carried back andforth along the air passages provided be- 4 tween the belts from the topof the oven to the base thereof, where it is finally delivered from thebelt 17 into a receiving hopper 30 having a door 31 which normally isclosed but which may be opened when it is desired to remove the materialfrom the machine.

Secured to the end wall 32 of the oven, that being the wall at the leftas shown in Figure 1, are deflector plates 33 which close off thepassage or space between the wall and ends of belts 13, 15 and 17.Likewise, secured to the opposite end walls 34 of the oven, aredefiector plates 35, which close off the passage between this wall andends of belts 9, 14 and 16. There is an air inlet pipe 36 leading intothe base of the oven, in which steam, or hot water pipes, 37 are locatedto heat the air admitted into the oven, and the dciiector plates are soarranged that the heated air is caused to circulate back and forthbetween the belts and in a direction opposite to their direction ofmovement until it finally reaches the top of the oven where it escapesthrough an outlet pipe 38 leading upwardly from the end of the ovenopposite the end wherein the hopper 3 is located. A damper 39 is mountedin the. pipe 38 and this Iray. be rotatably adjusted to control the flowo air.

In order that the air entering the machine may be maintained at anabsolutely standardized condition of both humidity and temperature, Ihave equipped the device with thermometers, as indicated at 40, andhydrometers as at 41, within the oven adjacent the air inlet and outletopenings. The air preferably would be drawn from an underground chamberin order to insure a uniformity of temperature and humidity and, bycontrolling the amount of heat generated by the steam pipes in the airinlet and, by adjustment ofthe damper to effect a faster or slowermovement of air through the machine, the desired conditions may bemaintained.

The means provided for driving the several conveyor belts consists fsprocket wheels 44, 45, 46, 47, 48, 49 and 50, which are fixedrespectively on the outer ends of the supporting shafts for the rollers,6, 11, 19, 21, 23, 25 and 27. These sprockets are made of such diameterthat the three upper belts move at the same speed of about sixty feetper hour, while the next two lower belts will move at about 45 feet perhour and the two bottom belts will be advanced at about thirty feet perhour. In this way, the belts will be kept filled with materialregardless of shrinkage of the dehydrated product. A chain belt 52operates about a motor driven sprocket wheel 53 and about the rollerdriving sprockets in such manner that the several belts are therebyadvanced in opposite directions, as is indicated by the arrows thereon.

It is also desired that an opening, as at 55, be placed in the top wallof the oven adjacent the hopper, so that the operator may properlydistribute the material over the feeding belt.

lVith the device so constructed and operated as described, it isapparent that the material is started in the process in an atmosphere ofa relatively high humidity that is derived from that moisture which haspreviously been extracted from the material farther advanced in therocess and that, in this way, no additiona moisture is required.

It is also apparent that the condition of the air at both the inlet andoutlet can be determined at all times by reading the instrumentsprovided and that should the conditions vary from those desired, theycan be made right by the variation of the amount of heat admitted or bythe control of the amount of air delivered through the machine.

If the proper humidity is not possible without additional moisture beingadded, this can be done by spraying fruit juices into the inlet pipe 36to be carried in with the air. In this way none of the desirable filialresults are lost. The means for spraying may consist of a spray nozzle60 mounted within a wall of the oven and which is connected by means ofa pipe 61 with a container 62 wherein the fruit juices may be containedunder air pressure. A valve 64 may be provided in the pipe to controlthe flow of the juices to the nozzle and the latter may be of suchcharacter that it will spray the juices into the air passage in a veryfinely atomized condition.

By the use of a machine of this character a better product is insuredsince the fruit fiavors and juices ordinarily lost by ordinary processof evaporation are retained.

Having thus described my invention, what I claim as new therein anddesire to secure by Letters-Patent is:

1. In a dehydrating machine, a dehydrating oven having a wall with anopening through which material may be fed into the oven and a conveyorbelt operating parallel with the wall beneath the opening, and cleatsfixed to the belt at closely spaced intervals for feeding material intothe oven and which extend close to the said wall to prevent the escapeof air from the oven by iiowing between the belt and wall to the feedingopening.

2. In a dehydrating machine, a preheating oven having a top wallprovided with a receiving opening, a dehydrating oven, a series ofconveyors for transferring material discharged from the preheating oventhrough the dehydrating oven, a conveyor belt operating within thepreheating oven beneath said receiving opening parallel with the Walland cleats fixed transversely to said belt and extending into closerelation with the Wall to provide separate Warming compartments intowhich definite amounts of the material may be delivered through thereceiving opening and Within which it is heated to the dehydratingtemperature before being delivered linto the dehydrating oven.

3. The process of dehydrating fruits and vegetables which consists ofadvancing the material to be dehydrated through an oppositely moving aircurrent which at the start is of high temperature and low humidity andat the end is of relatively low temperature and high humidity by theintroi duction into the air current of vaporized fruit juices.

Signed at Seattle, Washington, this 19th day of July, 1922.

CHARLES C. MACPHERRAN,

